The northern boundary of the Palm Island Inshore reporting zone extends east from the north-west bank of the Seaforth Channel mouth, just south of Hinchinbrook Island, to the offshore boundary and includes enclosed coastal, open coastal and mid-shelf waters.
The southern boundary of the Palm Island zone extends eastward from the southern boundary of the Herbert River Basin to just east of the Palm Island Group and runs north to the Wet Tropics NRM marine region boundary at the junction with the offshore waters boundary.
The major river discharging into the Palm Island zone is the Herbert River. Several sub-catchments, including the Seymour River, also discharge into the Palm Island inshore zone.
Water quality in the Palm Island zone is affected by plumes of sediments, nutrients and pesticides from rivers discharging directly into the zone but also from the plumes of southern rivers, particularly the Burdekin River the mouth of which is approximately 180 km to the south-east.
The area includes the Palm Island group located approximately 17 km east of the mainland. The Palm Island Group includes Orpheus Island, Pelorus Island, Fantome Island, Palm Island, and Havannah Island. These islands provide fringing shallow water environments that support coral reef ecosystems and reef seagrass meadows.
The diagram below shows the detailed results for each indicator by year. Click on the timeslider to see data from previous years.
Water quality for the Palm Island Inshore zone in 2016-17 is ‘good’ with a score of 64.
Water quality grades are based on water quality guideline trigger values established for the waters of the Great Barrier Reef Marine Park that, if exceeded, identify the need for management responses. The guidelines are not targets or assessments of pollutant loads entering the marine environment. The results are derived from in-situ water samples and water quality loggers at two inshore locations and passive pesticide samplers located Lucinda jetty.
The water clarity score of 54 (‘moderate’) in the Palm Island zone is comprised of total suspended solids (‘very poor’) and turbidity (‘very good’) indicators.
Nutrients scored 47 (‘moderate’) in the Palm Island zone, comprising of ‘very poor’ for oxidised nitrogen (NOx), a ‘moderate’ for particulate nitrogen (PN) and a ‘good’ for particulate phosphorus (PP).
The chlorophyll a score in the Palm Island zone is 67 (‘good’).
Using the Photosystem II herbicide equivalent concentrations method, pesticides received a score of 87 (‘very good’).
The water quality index has remained ‘good’ in the Palm Island zone since 2014-15.
The overall coral grade for the Palm Island inshore zone in 2016-17 is 49 (‘moderate’).
The coral grade is comprised of the density of juvenile hard corals score of 55 (‘very good’), the macroalgae cover score of 32 (‘poor’), the coral cover score of 33 (‘poor’), the change in coral cover score of 59 (‘moderate’), and the coral community composition score of 67 (‘good’).
The coral index in the Palm Island zone has remained a ‘moderate’ grade since 2014-15 and the index score of 49 has remained unchanged since 2015-16.
For the Palm Island zone a return of genera sensitive to water quality maintained the coral composition grade of ‘good’. Improvement of the coral change indicator resulting from pre-bleaching recovery of coral cover moderated the negative effects from the 2017 bleaching event on the index score. The full effect of bleaching in this zone will be more apparent when post-bleaching results from the remaining reef sites in the Palm Islands and Lady Elliot reef are reported for 2018.
More information on recent changes in coral indicators and the relationships with environmental conditions are provided in the latest Marine Monitoring Program coral report Thompson et al. (2018).
The fish index is currently under development and will be available in future report cards.
Further information on the methods used to produce the scores and grades and detailed results can be found here.